Connector

ABSTRACT

Proper alignment of threads when joints of casing are made up in hostile environments, such as on off-shore floating platforms subject to being buffeted by wave action, is provided by means of an improved box and pin connector. The pin has a substantially tapered threaded section whose small diameter end terminates in a lower guide section and whose large diameter is adjacent a larger diameter upper guide section. The box has a complementary section of internal oppositely tapered threads to mate with those on the pin as well as a smaller lower receptacle to receive the lower guide section on the pin and a larger receptacle to receive the upper guide section on the pin. In another version, both sets of threads are straight. The upper and lower guide sections on the pin and complementary receptacles in the box are mutually, partially engaged prior to engagement of the threads to guide the threads into proper alignment. The threads may have a back slant that prevents expansion of the box, and may have crests parallel to the longitudinal axis of the respective connector member to facilitate make up.

This is a continuation-in-part of copending U.S. application Ser. No.577,532 filed Feb. 6, 1984, now abandoned, which is a continuation ofapplication Ser. No. 373,114, filed Apr. 29, 1982, now U.S. Pat. No.4,429,904, which is a continuation-in-part of application Ser. No.280,302, filed July 6, 1981, now U.S. Pat. No. 4,410,204.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to connectors for cylindrical or tubular members,and more particularly to connectors for use on pipe and casing used inoil well drilling, or the like.

2. Description of the Prior Art

When a hole is bored into the earth, as for the production of oil andgas, a large diameter pipe known as surface casing is usually installedinto the upper section of the borehole. Surface casing stabilizes thewalls of the borehole near the surface where they are more apt to cavein. On holes drilled in offshore waters from platforms, or jack-ups, thepipe is extended from the ocean floor to the deck of the drillingstructure and is known as a marine riser. In such case, the riser is anextension of the surface casing and serves to prevent entry of sea waterinto the borehole.

Make up and installation of pipe such as surface casing from floatingoffshore drilling structures or vessels is complicated by the actions ofwaves on the vessel. Various motions of the vessel, of which the mostcritical are roll and pitch, render the make up of screw-typeconnections very difficult. Not only is it difficult to stab one casingsection into another, but it is also difficult to attain properalignment during make up, which can result in destructivecross-threading. While running casing of any kind is difficult in suchhostile environments, it is particularly difficult for larger casingstrings, such as twenty inches or larger. This is due not only to thegreater mass of such larger casing but also to the decrease in allowablemake-up angle for a given pitch thread as the pipe diameter increases.

To overcome these problems, the industry has resorted to use of largepitch (two or three threads per inch), tapered threads to assist in fastmake-up in hostile environments without cross threading. Unfortunately,such coarse threads concentrate stresses due to the depth of the threadsin relation to the load carrying cross-sectional thickness of theconnector. This greatly increases the likelihood of connector failure.Currently used connectors are also subject to failure if the box jointexpands, or "bells out," when the joint is under excessive tensionand/or bending type loads.

Accordingly, it is an object of the present invention to provide atechnique for connecting pipe such as casing, or the like, that iseasier to make up under hostile conditions such as those encountered onfloating drilling structures.

It is another object of the invention to provide a pipe connector thatis less susceptible to stress failure.

It is a further object of the invention to provide a connector that isless likely to "bell out" and thereby cause a connection failure.

It is a further object of the invention to provide threads whichfacilitate make up and which do not disengage due to expansion of thejoint.

Other objects and advantages of the invention will become apparent froma reading of the attached claims and description of the preferredembodiments.

SUMMARY OF THE INVENTION

These and other objects of the invention are attained by providing onelongitudinal member with an externally threaded end section and a secondlongitudinal member with an internally threaded tubular end sectionadapted to mate with the externally threaded section. The externallythreaded section is provided with a guide section adjacent the threadsat one end thereof and a smaller guide section at the other end. Theinternally threaded member is provided with a receptacle adjacent thethreads at one end thereof and sized to receive the smaller guidesection, and another receptacle adjacent the threads at the other endthereof and sized to receive the larger guide section. The guidesection, the corresponding receptacles, and the threads are adapted topermit engagement of the guide sections in the corresponding receptaclesprior to engagement of the threads. This enables proper alignment of thethreads before they are engaged and screwed together. The threads may betapered or straight, and may feature crests which are parallel to thelongitudinal axes of the respective members. In another aspect of theinvention, the threads on both the externally threaded section and theinternally threaded section are back tapered to provide slanted matingloading surfaces of the meshed teeth for lateral support to preventthread disengagement due to expansion of the internally threadedsection.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention may be better understood by reading the attacheddescription of preferred embodiments thereof in conjunction with theattached drawings wherein:

FIG. 1 is a longitudinal quarter section of a pin connector inaccordance with the present invention;

FIG. 2 is a longitudinal quarter section of a box connector suitable forreception of the pin connector of FIG. 1;

FIG. 3 is a fragment of a longitudinal cross section of the box and pinof FIGS. 1 and 2 in partial connection;

FIG. 4 is a view similar to FIG. 3 but with the box and pin connectorsof FIGS. 1 and 2 in full connection;

FIG. 5 is a view similar to FIG. 3 but with a slanted lower guidesection on the pin and a complementary slant on the corresponding boxreceptacle;

FIG. 6 is a view similar to FIG. 5 but with the box and pin connectorsof FIG. 5 in full connection;

FIG. 7 is a fragment of a longitudinal cross section of box and pinconnectors, in partial connection, with a slanted upper guide section onthe pin and a complementary slant on the corresponding box receptacle;

FIG. 8 is a view similar to FIG. 7 but with the pin and box connectorsof FIG. 7 in full connection;

FIG. 9 is a fragment of a longitudinal section of pin and box connectorsillustrating features of the internal and external threads; and

FIG. 10 is a longitudinal quarter section of a pin connector and a boxconnector, in partial connection, featuring straight threads.

DESCRIPTION OF PREFERRED EMBODIMENTS

Referring to FIGS. 1 and 2, a pin joint is shown generally at 10 in FIG.1 in alignment with and ready for insertion into a box joint showngenerally at 12 in FIG. 2. Pin 10 is shown above box 12, which is thepreferable arrangement for reasons to be outlined below.

Referring particularly to FIG. 1, pin 10 is attached to a cylindricalmember 14 by means of weld metal 16. Cylindrical member 14 may betubular in shape and have a bore 18. Pin 10 may also be tubular and havea bore 20 which may be an extension of bore 18 of longitudinal member14, which is cylindrical for casing applications.

Now describing the exterior of pin 10 in detail, generally from the topto the bottom on the drawing, pin 10 has a weld section 22 which isgenerally the same diameter as longitudinal member 14. Weld section 22provides an area for securing pin 10 to longitudinal member 14 with weldmetal 16. Next is an upset section 24 having a larger diameter than weldsection 22 and a tapered lower surface. Following upset section 24 is acylindrical upper guide section 26. Guide section 26 provides a flat(when viewed in longitudinal cross section) and serves to guide pin 10into box 12 in a manner hereinafter described. Next near the bottom ofpin 10 is a frustoconical section 28 having a multiplicity of continuousthreads 30 cut thereon. By "continuous" as used herein is meant that thethreads extend continuously, that is, essentially without a break, overthe threaded portion of the joint, or connector. However, one or morethread starts may be included in the threaded portion. Typically, thetaper of the frustoconical threaded surface is about three inches perfoot. At the upper base 32 of frustoconical section 28, threads 30 areessentially the same diameter, or slightly smaller, than that of upperguide section 26. Threads 30 taper down toward lower base 34. The taperof frustoconical thread section 28 is substantial and is chosen topermit threaded section 28 to travel substantially into the matingthreaded section in box 12 (described hereinbelow) before threadengagement begins. Nearest the lower end of pin 10 is a lower guidesection 36, having a bevelled lower edge 38. Guide section 36 isgenerally cylindrical in shape and, like upper guide section 22,provides a flat to insure thread alignment in a manner hereinafterdescribed. The bore 20 of pin 10 comprises two cylindrical voids definedby walls 40 and 42 connected by a frustoconical void defined by wall 44as shown. Void 42 is essentially the same diameter as bore 18 and islarger than void 40. Void 40 is bevelled at its lower end 46.

Referring now to FIG. 2, a box joint 12 for threaded mating with pin 10of FIG. 1 is shown. Box 12 is connected by means of weld metal 50 to alongitudinal member 52, which is tubular for casing applications. On itsexterior, box 12 comprises a cylindrical weld section 54 which isessentially the same diameter as longitudinal member 52 and provides anarea for welding to member 52 with weld metal 50. Adjacent to weldsection 54 and extending to the upper end of box 12 is a tubular endsection 56 which is larger in diameter than section 54 and has abevelled end 58. Section 56 has, in its interior, threads for matingwith threads 30 of pin 10, to be described hereinafter. The transitionfrom weld section 54 to end section 56 defines an annular shoulder 60,which is useful in supporting the member 52, and other like membersconnected thereto, when a tubular string is being made up, for example.For this reason, it is preferable that the box be oriented below thepin, since it is difficult or at least inconvenient to provide ashoulder on a pin such as 10.

Now describing the interior of box 12, longitudinal member 52 has acylindrical bore 62. Cylindrical bore 62 is in communication with agenerally cylindrical bore 66 in box 12. Nearest longitudinal member 52,bore 66 has a wall 68 defining a cylindrical void at weld section 54.Cylindrical section 68 is connected to a wall 72, defining a smallerdiameter cylindrical neck void of the bore 66, by means of afrustoconical void defined by wall 70. Next toward the top end of box 12is a cylindrical void defined by wall 74 and having a diameter largerthan void 72. A shoulder 73 connects the void 72 with the wall 74. Wall74 provides a flat for receiving lower guide portion 36 on pin 10 and isbroken by an annular groove 76 for receiving therein an O-ring sealingmember 78 sized to fit therein. Groove 76 is dove-tailed to hold theO-ring in place. The depth of annular groove 76 is slightly less thanthe diameter of the O-ring cross section so that the O-ring will providea pressure seal against guide section 36 of pin 10.

Next to inner guide wall 74 and toward the upper end of box 12 is afrustoconical void 80 having a multiplicity of continuous threads 81 ofthe same pitch as the threads 30 on threaded portion 28 on pin 10.Threaded void 80 is also sloped to matingly receive threaded portion 28of pin 10, having its smaller diameter lower base 82 adjacent to innerguide wall 74, and its larger upper base 84 toward the top end of box12. Nearest the top end of box 12 is an internal cylindrical voiddefined by wall 86 and having a bevelled lip 88 and sized to receiveupper guide portion 26 of pin 10. The combination of guide portion 26and void 86 acts to guide the threaded portion 28 on pin 10 and threadedportion 80 on box 12 together without cross-threading. Similar guidanceon the opposite end of threaded portion 28 and 80 is provided by thecombination of lower guide portion 36 and void 74.

Details of the connector threads may be appreciated by reference to FIG.9 wherein the threads 30 and 81 are meshed. The threads 30 and 81 onboth threaded portions 28 of pin 10 and 80 in box 12 typically have apitch of about four threads per inch, and a cone taper of three inchesper foot, with a half central angle A of approximately seven degrees,seven and one-half minutes relative to the respective pin and boxlongitudinal axes, which are common with the threads mated. The lowerside 90 of each thread 30 is bevelled downwardly typically at an angleof about forty-five degrees relative to the axis of the pin 10. Thethread crest 91 is parallel to the longitudinal axis of the pin 10. Theupper thread side 92 is bevelled downwardly and inwardly typicallyforming an acute angle of up to about eighty-five degrees relative tothe pin axis so that the thread surfaces 90 and 92 cooperate to formessentially a wedge shape. The thread roots 93 exhibit thethree-inch-per-foot taper of the thread cone 28 (FIG. 1). The boxthreads 81 are generally complementary to the pin threads 30. The lowerside 94 of each thread 81 is bevelled downwardly typically at an angleof up to about eighty-five degrees relative to the longitudinal axis ofthe box 12. If the acute angle formed between the upper face 92 of thepin thread 30 and the pin longitudinal axis, and the obtuse angle formedbetween the lower face 94 of the box thread 81 and the box longitudinalaxis, are each defined as the angle of orientation of the respectivethread surface, then the two thread surfaces 92 and 94 have mutuallysupplementary angles of orientation. The thread crest 95 is parallel tothe box longitudinal axis. The upper thread side 96 is bevelleddownwardly typically at an angle of about forty-five degrees relative tothe box axis so that the thread surfaces 94 and 96 cooperate to formessentially a wedge shape. The thread roots 97 exhibit thethree-inch-per-foot taper of the thread cone 80 (FIG. 2). The two setsof threads 30 and 81 mesh with back-slanted mating surfaces 92 on thepin threads and 94 on the box threads positioned mutually flat againsteach other. When such threads are fully engaged, the wedge shapes, andparticularly the wedging of the back-slanted mating surfaces 92 and 94,provide thread security not only down the length of the joint but alsoacross the width of the joint. This prevents the joint from failing dueto expansion of the box diameter during stress, a condition known as"belling." Additionally, the wedge effect provided by the back-slantedmating, or landing, surfaces 92 and 94 of the pin 10 and box 12,respectively, tends to more tightly mesh the threads 30 and 81 when thepin and box connection is under tension, wedging the pin threadsradially outwardly and the box threads radially inwardly into tighter,mutual threaded engagement.

Referring to FIG. 3 the manner of operation of the invention isillustrated by showing pin 10 and box 12 in partial engagement. To makeup the joint, a section of tubing with its pin joint 10 in the downposition is brought over another section of tubing with its box joint 12facing upwardly and longitudinally in line therewith. Box 12 may besupported by an elevator or other means engaging support shoulder 60.Thus it is preferred that the tubing string be made up with box joints12 facing upwardly and pin joints 10 facing downwardly to provideshoulders 60 for support.

When the smaller and lower end of pin 10 is sufficiently aligned withthe relatively larger upper end of box 12, pin 10 is lowered into box12. As pin 10 enters box 12, the downwardly bevelled lower side 90 ofthreads 30 on pin 10 may contact the bevelled lip 88 at the box wall 86and/or the upwardly bevelled upper sides 96 of threads 81 in box 12. Dueto the slant of the thread surface 90 and to the complementary bevelledfaces of threads 30 and 81, pin 10 continues to slide downwardly intobox 12, pin 10 being self-centering as it enters box 12. Similar slidingcontact may also be made between the bevelled upper edges 96 of threads81 and bevelled end 38 at lower guide portion 36. Further, the threadcrests 91 and 95 of the pin 10 and box 12, respectively, arecomplementary, being parallel to the pin and box longitudinal axes.Consequently, any interference to movement between the pin and boxduring make up due to friction, for example, in crest-to-crest contactbetween the threads 30 and 81 is reduced. Additionally, with the threadcrests 91 and 95 parallel to the longitudinal axes of the member (whichaxes are coincidental when the pin 10 and box 12 are connected), the pinmay be inserted into the box a greater distance without thread-to-threadengagement than if the thread crests parallel the respective threadcones, for example. Thus, the tapered threads 30 and 81 may overlapwithout mutual engagement by approximately the distance of the threadpitch, for example, more than if the crests 91 and 95 were not parallelto the member axes.

When pin 10 is centered in box 12, lower guide portion 36 enters guidevoid 74 and upper guide portion 26 enters guide void 86. The engagementof the flats (as viewed in cross section) provided by the wall of voids86 and 74 and the upper and lower guide portions 26 and 36,respectively, force vertical alignment of pin 10 with box 12. With thepin 10 and box 12 thus aligned, the lower guide section 36 may bereceived in the lower guide void 74, and the upper guide section 26 maybe received in the upper guide void 86, with no contact between the twosets of threads 30 and 81 as shown in FIG. 3. Thus, the two connectors10 and 12, and the tubular members 14 and 52, respectively, joinedthereto, are forced into alignment by the cooperation of the upper andlower guide-section-and-void combinations before the two sets of threads30 and 81 begin to mesh. Consequently, threads 30 on pin 10 and threads81 in box 12 are forced into alignment for proper thread engagement andheld that way before such engagement begins. Cross threading is therebyprevented.

At this point, pin 10 is further advanced into box 12 and rotated in theproper direction relative to box 12 to engage threads 30 and 81 and pullpin 10 downwardly into box 12 until the joint is tight. Typically, abouttwo turns would be required to tighten the joint once the threads wereinitially meshed. As lower guide portion 36 enters inner guide void 74,the lower guide portion 36 contacts the inside of O-ring 78, therebyproviding a seal between the interior and the exterior of the pipestring.

Referring to FIG. 4, pin 10 and box 12 are shown in a fully engagedposition. Travel of pin 10 into box 12 is limited by the seating of thepin end against the box internal shoulder 73. On the lower end of pin10, lower guide portion 36 is received within wall 74 defining the lowerguide void in box 12. A seal to prevent the movement of fluids betweenthe interior and exterior of the string is provided by O-ring 78 whichis positioned in an annular groove 76 and engaged with the guide surface36 acting as an annular seating surface. Locking engagement of threads30 on pin 10 with threads 81 on box 12 is provided by the wedging of theupper faces 92 of threads 30 with the lower faces 94 of threads 81 (FIG.9). The thread surfaces 92 and 94 are thus mutually wedged and flatagainst each other with no contact between the pin thread crests 91 andthe box thread roots 97, no contact between the pin roots 93 and the boxcrests 95, and no contact between the lower pin thread surface 90 andthe upper box thread surface 96. These surfaces do not contact with thethreads 30 and 81 fully wedged because the bottom of the pin 10 abutsthe box shoulder 73 before such contact can be effected. Thus, theback-slanted, wedging surfaces 92 and 94 are fully loaded with theforces locking the pin 10 and box 12 together. Further, the mutualwedging engagement of the back slanted threads prevents box 12 fromexpanding and thereby thread disengagement due to belling out of the boxsince any tendency of the box to expand results in the pin threadspulling radially inwardly on the box threads. Additionally, the wedgingengagement of the threads 30 and 81 tightens as the pin and boxconnection is subject to tension.

As a pin connector is stabbed into a box connector, as shown in FIG. 3for example, the combination of the upper guide section 26 and the upperreceptacle surface 86 and the combination of the lower guide surface 36with the lower receptacle surface 74 operate to align the pin withrespect to the box such that the maximum angular misalignment possibleis less than would allow the pin and box threads to cross thread. Thus,the combined clearance between the combination of the upper surfaces 26and 86 and between the lower surfaces 36 and 74 cannot exceed a valuedetermined by the diameter of the threads, the number of threads perinch and the vertical distance between the two sets of surfaces 26; 86and 36; 74. However, for ease of stabbing and reliability in field use,it is desirable to have clearances between the surfaces 26 and 86 andbetween the surfaces 36 and 74 that are as large as possible and whichstill prevent cross threading. But when the pin 10 is fully mated withthe box 12 as shown in FIG. 4, the clearance between the lower guidesurface 36 and the corresponding receptacle surface 74 must besufficiently small to achieve a reliable seal therebetween by means ofthe O-ring seal member 78. Since there is no seal requirement betweenthe upper guide surface 26 and the corresponding receptacle wall 86, anespecially small clearance between these surfaces in the made upconfiguration of FIG. 4 is not required.

The present invention is also embodied in a pin joint indicatedgenerally at 10' in FIGS. 5 and 6, and a box joint indicated generallyat 12' in FIGS. 5 and 6. In FIG. 5 the pin 10' is shown aligned with andpartially inserted within the box 12', but without mutual meshingengagement of the threads 30 and 81 carried by the pin and box,respectively. In FIG. 6, the connection between the pin 10' and the box12' is complete, with wedging mating of the pin threads 30 with the boxthreads 81, and abutment of the bottom surface of the pin against theinternal shoulder 73 of the box. With exceptions as noted hereinafter,the design of the pin 10' may be like that of the previously illustratedand described pin 10, and similarly the design of the box 12', withexceptions noted hereinafter, may be like that of the previouslyillustrated and described box 12. Thus, an upper cylindrical guidesurface 26 carried by the pin 10' cooperates with an internalcylindrical wall, or receptacle, 86 of the box 12' in the alignment ofthe pin and box to avoid cross threading of the pin and box threads 30and 81, respectively. However, rather than a cylindrical lower guidesection, the pin 10' features a frustoconical lower guide surface 36',tapering downwardly and radially inwardly and ending in a bevelled edge38'. Similarly, rather than a cylindrical lower flat, or receptacle, thepin 12' features a frustoconical internal surface 74', that also tapersdownwardly and radially inwardly as illustrated in FIGS. 5 and 6. Theacute angles of taper of the two surfaces 36' and 74' are preferably thesame, and may be on the order of a few degrees, for example, relative tothe axes of the pin 10' and box 12', respectively. The conicalreceptacle surface 74' is broken by a dove-tailed annular groove 76' inwhich is mounted an O-ring sealing member 78 for sealing engagement withthe conical guide surface 36' when the pin 10' and box 12' are fullymated as illustrated in FIG. 6.

During the make up of the pin 10' with the box 12', the conical guidesurface 36' cooperates with the tapered receptacle surface 74' to insuresufficient alignment of the pin and box to avoid cross threading.Nevertheless, as shown in FIG. 5, there is sufficient clearance betweenthe surfaces 36' and 74' in the configuration of FIG. 5 to allowsufficient lateral movement between the pin 10' and the box 12' tofacilitate stabbing of these two elements, and further to avoid extendedrubbing of the O-ring seal member 78 around and along the pin surface36'. Such relatively extensive wear on an O-ring seal member is to beavoided if possible as a potential cause of damage to the seal memberand consequent leaking. It will be appreciated by reference to FIG. 5that the maximum lateral clearance between the pin surface 36' and thebox surface 74', with the two surfaces overlapping, occurs just as thesurfaces begin to overlap as the pin 10' is moved longitudinally withinthe box 12'. The clearance between the surfaces 36' and 74' is minimizedin the configuration shown in FIG. 6 wherein the threads 30 and 81 aremutually meshed and wedging the bottom of the pin 10' against theshoulder 73 of the box 12'. In that configuration, the clearance betweenthe pin surface 36' and the box surface 74' is reduced to insure sealingengagement therebetween by means of the O-ring seal member 78.

The angle of taper of the pin guide surface 36' and that of thereceptacle surface 74' may be varied, but is to be kept sufficientlysmall in any case to insure that cross threading is prohibited.Consequently, the permitted angle of the surfaces 36' and 74' relativeto the common longitudinal axis of the pin 10' and box 12' in the matedconfiguration of FIG. 6, for example, is smaller for larger diameterthreads.

Still another variation of guide and receptacle surfaces in accordancewith the present invention is shown in FIGS. 7 and 8, wherein a portionof a pin joint is indicated generally at 10" and a portion of a boxjoint is indicated at 12". In FIG. 7 the pin 10" and box 12" aremutually aligned but not threadedly engaged; in FIG. 8 the pin 10" andbox 12" are fully made up, with the pin threads 30 meshed and wedgedwith the box threads 81. The pin 10", with exceptions discussedhereinafter, may be designed like the pin 10 or the pin 10' previouslyillustrated and described. Similarly, the box 12", with exceptions notedhereinafter, may be designed like pin 12 or pin 12' previouslyillustrated and described. However, the pin 10" features an upper guidesurface 26' that is frustoconical, tapering downwardly and radiallyinwardly as viewed in FIGS. 7 and 8. Similarly, the box 12" features anupper inner receptable wall 86' that is also frustoconical, taperingdownwardly and radially inwardly as viewed in FIGS. 7 and 8. The acuteangles of taper of the pin guide surface 26' and of the box receptaclewall 86', measured relative to the pin and box longitudinal axes,respectively, are preferably the same, and are typically on the order ofa few degrees. An upset section 24' is separated from the conical upperguide section 26' by a tapered surface, and abuts a bevelled edge 88' ofthe box receptacle surface 86' in the made up configuration illustratedin FIG. 8.

The combination of the frustoconical guide surface 26' and receptaclesurface 86' provides advantages similar to those provided by thefrustoconical lower guide surface 36' and the correspondingfrustoconical receptacle surface 74' of FIGS. 5 and 6 while stillserving to ensure proper pin and box mutual alignment to avoid crossthreading. Tapering the upper guide surface 26' and the correspondingreceptacle surface 86' as illustrated in FIGS. 7 and 8, for example,increases the lateral clearance therebetween to facilitate stabbing ofthe pin 10" within the box 12". This lateral clearance between theoverlapped guide surface 26' and the receptacle surface 86' is maximizedwhen the pin 10" is positioned relative to the box 12" during make up sothat the two surfaces 26' and 86' just begin to overlap. As the pin 10"is further inserted within the box 12", the lateral clearance betweenthe surfaces 26' and 86' reduces to a minimum, achieved in thecompletely made up configuration illustrated in FIG. 8. The angle oftaper of the surfaces 26' and 86' may be increased to increase themaximum lateral clearance between these two surfaces in an initialoverlap configuration for the purpose of facilitating stabbing. However,in any case, the angle of taper must be sufficiently small to insurethat the pin 10" and box 12" are not permitted to be mutually misalignedsufficiently to allow cross threading during make up. The same type offactors which dictate the upper limit of taper angle for surfaces 36'and 74' of FIGS. 5 and 6 determines the upper limit of taper angle forthe upper guide surface 26' and the corresponding receptacle surface86'. Thus, for example, the upper limit of the taper angle for thesurfaces 26' and 86' decreases as the diameter of the pin threads 30 andbox threads 81 increases.

The present invention is also embodied in a pin joint indicatedgenerally at 110, and a box joint indicated generally at 112, in FIG.10, wherein the pin is shown aligned with and partially inserted withinthe box, but without mutual meshing engagement of threads 114 and 116carried by the pin and box, respectively. With exceptions as notedhereinafter, the design of the pin 110 may be like that of thepreviously described and illustrated pin 10, and similarly the design ofthe box 112, with exceptions noted hereinafter, may be like that of thepreviously described and illustrated box 12. Thus, an upper cylindricalguide surface 118 carried by the pin 110 cooperates with an upperinternal cylindrical wall, or receptacle, 120 of the box 112, and alower cylindrical guide surface 122 carried by the pin cooperates with alower internal cylindrical wall, or receptacle, 124 of the box 112, inaligning the pin and box to avoid cross-threading of the pin and boxthreads 114 and 116, respectively. The cylindrical receptacle surface124 is broken by a dove-tailed annular groove 126 in which is mounted anO-ring sealing member 128 for sealing engagement with the cylindricalguide surface 122 when the pin 110 and box 112 are made up.

The pin threads 114 and box threads 116 are straight, or parallel, andare generally mutually complementary for providing threaded engagementbetween the pin 110 and the box 112. Generally, any thread form may beutilized to provide the pin threads 114 and box threads 116, includingbut not limited to the thread forms described hereinbefore andillustrated in detail in FIG. 9. Thus, for example, the loading surfacesof the threads 114 and 116 may be back slanted to provide a wedgingeffect between the threads when meshed, and, for example, the threadcrests may be parallel to the longitudinal axes of the respective pin orbox member.

It will further be appreciated that the straight threads 114 and 116 maybe utilized with tapered, or frustoconical guide surfaces andreceptacles as illustrated, for example, in FIGS. 5-8. Thus, straightthreads such as the pin threads 114 and box threads 116 may be utilizedwith cylindrical guide surfaces and receptacles above and below therespective threads, as illustrated in FIG. 10, frustoconical guide andreceptacle surfaces both above and below the threads, cylindrical guideand receptacle surfaces above the threads combined with frustoconicalguide and receptacle surfaces below the threads, or frustoconical guideand receptacle surfaces above the threads combined with cylindricalguide and receptacle surfaces below the threads.

Whatever combination of forms of guide surfaces and receptacles isutilized with the straight threads 114 and 116, the lateral dimensionsof the threads, guide surfaces and receptacles both above and below thethreads, are such that the lower pin guide surface may pass beyond thebox threads to begin to engage the lower box receptacle, and the pinthreads may pass within the upper box receptacle, and the upper pinguide surface may begin to engage the upper box receptacle, beforemeshing engagement between the pin and box threads can occur.Consequently, as in the case of the tapered thread embodiments of thepresent invention, the present invention utilizing straight threadsprovides a pin and box connector combination wherein the upper and lowerguide surfaces of the pin operatively engage the upper and lowerreceptacles of the box, respectively, to align the pin and boxconnectors prior to threaded engagement of the threads carried by thetwo connectors to prevent any tendency of the connector members to crossthread during makeup.

With the guide surfaces 118 and 122 cooperating with the receptacles 120and 124, respectively, to align the pin 110 and box 112 to avoid crossthreading, the pin may be further inserted into the box to engage thepin threads 114 with the box threads 116. Thereafter, mutual rotationalmovement between the pin 110 and the box 112 meshes the pin threads 114with the box threads 116 to make up the connection between the twomembers while the pin is further advanced into the box. When the pin 110is advanced into the box so that the lower annular surface 130 of thepin abuts the upwardly facing, annular shoulder 132 of the box, theconnection between the pin and box is complete with the threads 114 and116 loaded by the rotation between the pin and box to tighten themeshing of the threads. Also, with the make up complete, the O-ring seal128 provides sealing with the lower pin guide surface 122 acting as aseating surface. Reverse rotational movement between the pin 110 and box112 releases the two connector members for separation.

A pin and box connector combination according to the present inventionmay be equipped with an upper guide surface and receptacle combinationfeaturing cylindrical surfaces and a lower guide surface and receptaclecombination which also features cylindrical surfaces, as illustrated inFIGS. 1-4 and 10. A combination of upper guide surface and correspondingreceptacle featuring cylindrical surfaces, as shown in FIGS. 1-4, may beincluded in a pin and box combination according to the present inventionwith a lower guide surface and corresponding receptacle surface whichare generally frustoconical, as illustrated in FIGS. 5 and 6. Thepresent invention may also be provided with an upper guide surface andcorresponding receptacle surface featuring frustoconical surfaces, as inFIGS. 7 and 8, in combination with a lower guide surface andcorresponding receptacle surface which are cylindrical, as in FIGS. 1-4.Additionally, a pin and box combination according to the presentinvention may feature an upper guide surface and receptacle combinationwhich is frustoconical, as shown in FIGS. 7 and 8, and a lower guidesurface and receptacle surface which are also generally frustoconical,as illustrated in FIGS. 5 and 6. Further, a connector combinationaccording to the present invention may include complementary taperedthreads as shown in FIGS. 1-9, or straight threads as in FIG. 20, withback slanted landing surfaces and/or crests parallel to the longitudinalaxis of the respective connector member, as shown in FIG. 9, and in anycombination of cylindrical and/or frusto-conical guide and receptaclepairs.

The present invention provides a connector assembly including first andsecond generally complementary threaded connector members, with oneconnector member carrying first and second guide sections receivable byfirst and second voids, or receptacles, respectively, as parts of theother connector member. The threaded sections may be either tapered orstraight. The two connector members may be partially joined with theguide sections partially inserted into the respective receptacles,whereby the threads, whether tapered or straight, are forced into mutualalignment to avoid cross threading, through the threads are not mutuallyengaged. The two sets of threads may include back-slanted load, orlanding, surfaces to provide a wedge effect when mutually engaged,urging the connector members into tighter threaded engagement inresponse to forces tending to expand the outer connector member. Pin andbox thread crests, being parallel to the pin and box longitudinal axes,facilitate make up. The pin end abuts a box shoulder to complete make upwithout the pin and box threads closing fully laterally. Thus, the jointmay be completely made up, with the threads and shoulder loaded, withrelatively low torque applied as compared to joints wherein the threadsmust mesh completely, for example. A seal carried by one connectormember seats against an appropriate surface on the other member to sealthe two connector members together.

While particular embodiments of the present invention and the method ofuse thereof have been shown and described, it is evident that minorchanges may be made therein without departing from the true scope andspirit of the invention. It is the intention in the appended claims tocover all such changes and modifications.

What is claimed is:
 1. A connector assembly comprising:a. a firstconnector member including a first guide section and a second guidesection axially displaced from, and of generally lesser external lateraldimension than, said first guide section; b. a second connector memberfor receiving said first connector member, including a first receptacle,for receiving said first guide section, and a second receptacle, forreceiving said second guide section, axially displaced from and ofgenerally lesser internal lateral dimension than said first receptacle;c. tapered external threads, as part of said first member, positionedgenerally axially between said first and second guide sections andhaving crests parallel to the longitudinal axis of said first member;and d. tapered internal threads, as part of said second member,positioned generally axially between said first and second receptacles,having crests parallel to the longitudinal axis of said second member,and generally complementary to said external threads for threadedengagement therewith; e. wherein said first and second guide sectionsmay be partially received by said first and second receptacles,respectively, to align said first and second members without threadedengagement between said external and internal threads.
 2. An assembly asdefined in claim 1 further comprising seal means carried by one of saidmembers for sealingly engaging the other of said members when said firstand second members are connected together in threaded engagement betweensaid external and internal threads.
 3. An assembly as defined in claim1:a. wherein said external threads comprise back slanted landingsurfaces; b. wherein said internal threads comprise back slanted landingsurfaces; and c. wherein the meshing of said external and internalthreads provides a wedging effect between said respective back slantedlanding surfaces urging said external and internal threads into tighterengagement in response to forces tending to expand said second member;and d. further comprising first and second abutment means carried bysaid first and second members, respectively, whereby said first andsecond members may be completely connected with said first and secondabutment means in mutual abutting engagement and said back slantedlanding surfaces mutually wedged, but without said external and internalthreads completely meshed.
 4. An assembly as defined in claim 1wherein:a. the taper of said external threads varies approximately fromthe lateral dimension of said first guide section adjacent said threadsto that of said second guide section adjacent said threads; and b. thetaper of said internal threads varies approximately from the lateraldimension of said first receptacle adjacent said threads to that of saidsecond receptacle adjacent said threads.
 5. An assembly as defined inclaim 1 wherein said second guide section is adjacent the end of saidfirst member and said first receptacle is adjacent the end of saidsecond member.
 6. An assembly as defined in claim 1 further comprisingexternal shoulder means as part of said second member for supportingsaid second member.
 7. As assembly as defined in claim 1 wherein one ofsaid guide sections comprises a frustoconical surface and thecorresponding receptacle comprises a frustoconical surface. 8.Connecting apparatus comprising:a. an externally threaded member, thethreads thereon being substantially tapered downwardly toward an end ofsaid externally threaded member and having crests parallel to thelongitudinal axis of said externally threaded member; b. said externallythreaded member further having a first guide section on one axial sideof said threads and a second guide section on the other axial side ofsaid threads; c. an internally threaded tubular member, the threadsthereon being substantially tapered to complementarily receive saidthreads on said externally threaded member and having crests parallel tothe longitudinal axis of said internally threaded member; d. saidinternally threaded member further having a first receptacle on oneaxial side of said internal threads and a second receptacle on the otheraxial side of said threads, which receptacles are sized tocomplementarily receive said first and second guide sections of saidexternally threaded member, respectively; and e. said taper of saidthreads of both said externally threaded member and said internallythreaded member permitting engagement of said first and second guidesections with said first and second receptacles, respectively, prior tomutual threaded engagement of said threads of said externally andinternally threaded members.
 9. Apparatus as defined in claim 8:a.wherein said threads on said externally threaded member comprise backslanted landing surfaces; b. wherein said threads on said internallythreaded member comprise back slanted landing surfaces; and c. whereinthe meshing of said external and internal threads provides a wedgingeffect between said respective back slanted landing surfaces urging saidexternal and internal threads into tighter engagement in response toforces tending to expand said internally threaded member; and d. furthercomprising first and second abutment means carried by said externallyand internally threaded members, respectively, whereby said members maybe completely connected with said first and second abutment means inmutual abutting engagement and said back slanted landing surfacesmutually wedged, but without said external and internal threadscompletely meshed.
 10. Apparatus as defined in claim 8 wherein:a. thetaper of said external threads varies approximately from the lateraldimension of said first guide section adjacent said threads to that ofsaid second guide section adjacent said threads; and b. the taper ofsaid internal threads varies approximately from the lateral dimension ofsaid first receptacle adjacent said threads to that of said secondreceptacle adjacent said threads.
 11. Apparatus as defined in claim 8further comprising external shoulder means as part of said internallythreaded member for supporting said member.
 12. Apparatus as defined inclaim 8 wherein one of said guide sections comprises a frustoconicalsurface and the corresponding receptacle comprises a frustoconicalsurface.
 13. Apparatus as defined in claim 8 further comprising sealmeans for sealingly connecting said externally and internally threadedmembers when said threads of said two members are in threadedengagement.
 14. A pipe joint comprising:a. a tubular section; b. aninternally threaded box connector on one end of said tubular section,said threads having crests parallel to the longitudinal axis of saidconnector; c. an externally threaded pin connector on the other end ofsaid tubular section, said threads having crests parallel to thelongitudinal axis of said connector; d. a first guide section on saidpin connector at one end of said threads thereon; e. a second guidesection on said pin connector at the other end of said threads thereon;f. a first receptacle in said box connector at one end of said threadstherein, said first receptacle adapted to receive such first guidesection of a like pipe joint; and g. a second receptacle in said boxconnector at the other end of said threads therein, said secondreceptacle adapted to receive such second guide section of a like pipejoint; h. wherein such first receptacle may receive such first guidesection, and such second receptacle may receive such second guidesection, of a like pipe joint prior to threaded engagement of suchthreads on such pin connector and in such box connector.
 15. A pipejoint as defined in claim 14 wherein said first guide section and saidfirst receptacle generally are larger in lateral dimension than saidsecond guide section and said second receptacle.
 16. A pipe joint asdefined in claim 14 wherein said threads on said pin and in said box aregenerally tapered from the lateral dimensions of said first guidesection and said first receptacle adjacent said pin and box threads,respectively, to the lateral dimensions of said second guide section andsaid second receptacle adjacent said pin and box threads, respectively.17. A pipe joint as defined in claim 14 wherein said threads of said pinconnector and said threads of said box connector are each back slantedto provide a wedge effect urging a tighter threaded engagement betweensuch complementary connectors of like pipe joints in response to forcestending to expand said box connector.
 18. A pipe joint as defined inclaim 14 further comprising seal means carried by said box connector andseat means as part of said pin connector wherein such seal means maysealingly engage such seat means of a like pipe joint when such pin andbox connectors are engaged to connect said pipe joints.
 19. A pipe jointas defined in claim 14 wherein at least one of said guide sectionscomprises a frustoconical surface, and the corresponding receptaclecomprises a frustoconical surface.
 20. A method of making a threadedconnection between first and second longitudinal members, said membersincluding generally complementary tapered threads with each set ofthreads having crests parallel to the longitudinal axis of therespective member, comprising the steps of:a. inserting an end of saidfirst longitudinal member into an end of said second longitudinalmember; b. inserting a first guide section on said first longitudinalmember in a first receptacle in said second longitudinal member andinserting a second guide section on said first longitudinal member in asecond receptacle in said second longitudinal member to align said firstand second members; c. thereafter meshing threads of said first andsecond longitudinal members; and d. rotating one said longitudinalmember relative to the other said longitudinal member to fully engagesaid threads.
 21. A connector assembly comprising:a. a first connectormember including a first guide section and a second guide sectionaxially displaced from, and of generally lesser external lateraldimension than, said first guide section; b. a second connector memberfor receiving said first connector member, including a first receptacle,for receiving said first guide section, and a second receptacle, forreceiving said second guide section, axially displaced from and ofgenerally lesser internal lateral dimension than said first receptacle;c. continuous tapered external threads, as a part of said first member,positioned generally axially between said first and second guidesections; and d. continuous tapered internal threads, as part of saidsecond member, positioned generally axially between said first andsecond receptacles and generally complementary to said external threadmeans for threaded engagement therewith; e. wherein one of said guidesections comprises a frustoconical surface and the correspondingreceptacle comprises a frustoconical surface; and f. wherein said firstand second guide sections may be partially received by said first andsecond receptacles, respectively, to align said first and second memberswithout threaded engagement between said external and internal threads.22. An assembly as defined in claim 21 further comprising seal meanscarried by one of said members for sealingly engaging the other of saidmembers when said first and second members are connected together inthreaded engagement between said external and internal threads.
 23. Anassembly as defined in claim 21 wherein:a. said external threadscomprise back slanted landing surfaces; b. said internal threadscomprise back slanted landing surfaces; and c. the meshing of saidexternal and internal threads provides a wedging effect between saidrespective back slanted landing surfaces urging said external andinternal threads into tighter engagement in response to forces tendingto expand said second member.
 24. As assembly as defined in claim 23further comprising first and second abutment means carried by said firstand second members, respectively, whereby said first and second membersmay be completely connected with said first and second abutment means inmutual abutting engagement and said back slanted landing surfacesmutually wedged, but without said external and internal threadscompletely meshed.
 25. An assembly as defined in claim 21 wherein:a. thecrests of said external threads are parallel to the longitudinal axis ofsaid first member; and b. the crests of said internal threads areparallel to the longitudinal axis of said second member.
 26. An assemblyas defined in claim 21 wherein:a. the taper of said external threadsvaries approximately from the lateral dimension of said first guidesection adjacent said threads to that of said second guide sectionadjacent said threads; and b. the taper of said internal threads variesapproximately from the lateral dimension of said first receptacleadjacent said threads to that of said second receptacle adjacent saidthreads.
 27. An assembly as defined in claim 21 wherein said secondguide section is adjacent the end of said first member and said firstreceptacle is adjacent the end of said second member.
 28. An assembly asdefined in claim 21 further comprising external shoulder means as partof said second member for supporting said second member.
 29. Connectingapparatus comprising:a. an externally threaded member, the threadsthereon being continuous and substantially tapered downwardly toward anend of said externally threaded member; b. said externally threadedmember further having a first guide section on one axial side of saidthreads and a second guide section on the other axial side of saidthreads; c. an internally threaded tubular member, the threads thereonbeing continuous and substantially tapered to complementarily receivesaid threads on said externally threaded member; d. said internallythreaded member further having a first receptacle on one axial side ofsaid internal threads and a second receptacle on the other axial side ofsaid threads, which receptacles are sized to complementarily receivesaid first and second guide sections of said externally threaded member,respectively, and wherein one of said guide sections and thecorresponding receptacle comprise frustoconical surfaces; and e. saidtaper of said threads of both said externally threaded member and saidinternally threaded member permitting engagement of said first andsecond guide sections with said first and second receptacles,respectively, prior to mutual threaded engagement of said threads ofsaid externally and internally threaded members.
 30. Apparatus asdefined in claim 29 wherein:a. said threads on said externally threadedmember comprise back slanted landing surfaces; b. said threads on saidinternally threaded member comprise back slanted landing surfaces; andc. the meshing of said external and internal threads provides a wedgingeffect between said respective back slanted landing surfaces urging saidexternal and internal threads into tighter engagement in response toforces tending to expand said internally threaded member.
 31. Apparatusas defined in claim 30 further comprising first and second abutmentmeans carried by said externally and internally threaded members,respectively, whereby said members may be completely connected with saidfirst and second abutment means in mutual abutting engagement and saidback slanted landing surfaces mutually wedged, but without said externaland internal threads completely meshed.
 32. Apparatus as defined inclaim 29 wherein:a. the crests of said external threads are parallel tothe longitudinal axis of said externally threaded member; and b. thecrests of said internal threads are parallel to the longitudinal axis ofsaid internally threaded member.
 33. Apparatus as defined in claim 29wherein:a. the taper of said external threads varies approximately fromthe lateral dimension of said first guide section adjacent said threadsto that of said second guide section adjacent said threads; and b. thetaper of said internal threads varies approximately from the lateraldimension of said first receptacle adjacent said threads to that of saidsecond receptacle adjacent said threads.
 34. Apparatus as defined inclaim 29 further comprising external shoulder means as part of saidinternally threaded member for supporting said member.
 35. Apparatus asdefined in claim 29 further comprising seal means for sealinglyconnecting said externally and internally threaded members when saidthreads of said two members are in threaded engagement.
 36. A pipe jointcomprising:a. a tubular section; b. an internally threaded box connectoron one end of said tubular section; c. an externally, continuouslythreaded pin connector on the other end of said tubular section; d. afirst guide section on said pin connector at one end of said threadsthereon; e. a second guide section on said pin connector at the otherend of said threads thereon; f. a first receptacle in said box connectorat one end of said threads therein, said first receptacle adapted toreceive such first guide section of a like pipe joint; and g. a secondreceptacle in said box connector at the other end of said threadstherein, said second receptacle adapted to receive such second guidesection of a like pipe joint; h. wherein such first receptacle mayreceive such first guide section, and such second receptacle may receivesuch second guide section, of a like pipe joint prior to threadedengagement of such threads on such pin connector and in such boxconnector; and i. wherein at least one of said guide sections comprisesa frustoconical surface and the corresponding receptacle comprises afrustoconical surface.
 37. A pipe joint as defined in claim 36 whereinsaid first guide section and said first receptacle generally are largerin lateral dimension than said second guide section and said secondreceptacle.
 38. A pipe joint as defined in claim 36 wherein said threadson said pin and in said box are generally tapered from the lateraldimensions of said first guide section and said first receptacleadjacent said pin and box threads, respectively, to the lateraldimensions of said second guide section and said second receptacleadjacent said pin and box threads, respectively.
 39. A pipe joint asdefined in claim 36 wherein said threads of said pin connector and saidthreads of said box connector are each back slanted to provide a wedgeeffect urging a tighter threaded engagement between such complementaryconnectors of like pipe joints in response to forces tending to expandsaid box connector.
 40. A pipe joint as defined in claim 36 furthercomprising seal means carried by said box connector and seat means aspart of said pin connector wherein such seal means may sealingly engagesuch seat means of a like pipe joint when such pin and box connectorsare engaged to connect said pipe joints.
 41. A pipe joint as defined inclaim 36 wherein the crests of said threads of said pin connector andthe crests of said threads of said box connector are parallel to thelongitudinal axis of said pipe joint.
 42. A method of making a threadedconnection between first and second longitudinal members, said membersincluding generally complementary, continuous tapered threads,comprising the steps of:a. inserting an end of said first longitudinalmember into an end of said second longitudinal member; b. aligning saidfirst and second members by inserting a first guide section on saidfirst longitudinal member in a first receptacle in said secondlongitudinal member and inserting a second guide section on said firstlongitudinal member in a second receptacle in said second longitudinalmember wherein said first and second guide sections and said first andsecond receptacles are on opposite axial sides of said threads of saidfirst and second members, respectively, and one of said guide sectionsand the corresponding receptacle comprise frustoconical surfaces; c.thereafter meshing threads of said first and second longitudinalmembers; and d. rotating one said longitudinal member relative to theother said longitudinal member to fully engage said threads.
 43. Aconnector assembly comprising:a. a first connector member including afirst guide section and a second guide section axially displaced from,and of generally lesser external lateral dimension than, said firstguide section; b. a second connector member for receiving said firstconnector member, including a first receptacle, for receiving said firstguide section, and a second receptacle, for receiving said second guidesection, axially displaced from and of generally lesser internal lateraldimension than said first receptacle; c. continuous, straight, externalthreads, as part of said first member, positioned generally axiallybetween said first and second guide sections; d. continuous, straight,internal threads, as part of said second member, positioned generallyaxially between said first and second receptacles and generallycomplementary to said external threads for threaded engagementtherewith; and e. first and second abutment means carried by said firstand second members, respectively, whereby said first and second membersmay be completely connected with said first and second abutment means inmutual abutting engagement and with said external and internal threadsloaded; f. wherein said first and second guide sections may be partiallyreceived by said first and second receptacles, respectively, to alignsaid first and second members without threaded engagement between saidexternal and internal threads.
 44. An assembly as defined in claim 43further comprising seal means carried by one of said members forsealingly engaging the other of said members when said first and secondmembers are connected together in threaded engagement between saidexternal and internal threads.
 45. An assembly as defined in claim 43wherein:a. said external threads comprise back slanted landing surfaces;b. said internal threads comprise back slanted landing surfaces; and c.the meshing of said external and internal threads provides a wedgingeffect between said respective back slanted landing surfaces urging saidexternal and internal threads into tighter engagement in response toforces tending to expand said second member.
 46. An assembly as definedin claim 43 wherein:a. the crests of said external threads are parallelto the longitudinal axis of said first member; and b. the crests of saidinternal threads are parallel to the longitudinal axis of said secondmember.
 47. An assembly as defined in claim 43 wherein said second guidesection is adjacent the end of said first member and said firstreceptacle is adjacent the end of said second member.
 48. An assembly asdefined in claim 43 further comprising external shoulder means as partof said second member for supporting said second member.
 49. Connectingapparatus comprising:a. an externally, continuously threaded member, thethreads thereon being straight; b. said externally threaded memberfurther having a first guide section on one axial side of said threadsand a second guide section on the other axial side of said threads; c.an internally, continuously threaded tubular member, the threads thereonbeing straight and generally complementary to said threads on saidexternally threaded member; d. said internally threaded member furtherhaving a first receptacle on one axial side of said internal threads anda second receptacle on the other axial side of said threads, whichreceptacles are sized to complementarily receive said first and secondguide sections of said externally threaded member, respectively; and e.first and second abutment means carried by said externally andinternally threaded members, respectively, whereby said members may becompletely connected with said first and second abutment means in mutualabutting engagement and with said external and internal threads loaded;f. wherein said first and second guide sections may engage said firstand second receptacles, respectively, prior to mutual threadedengagement of said threads on said externally and internally threadedmembers.
 50. Apparatus as defined in claim 49 wherein:a. said threads onsaid externally threaded member comprise back slanted landing surfaces;b. said threads on said internally threaded member comprise back slantedlanding surfaces; and c. the meshing of said external and internalthreads provides a wedging effect between said respective back slantedlanding surfaces urging said external and internal threads into tighterengagement in response to forces tending to expand said internallythreaded member.
 51. Apparatus as defined in claim 49 wherein:a. thecrests of said external threads are parallel to the longitudinal axis ofsaid externally threaded member; and b. the crests of said internalthreads are parallel to the longitudinal axis of said internallythreaded member.
 52. Apparatus as defined in claim 49 further comprisingexternal shoulder means as part of said internally threaded member forsupporting said member.
 53. Apparatus as defined in claim 49 furthercomprising seal means for sealingly connecting said externally andinternally threaded members when said threads of said two members are inthreaded engagement.
 54. A pipe joint comprising:a. a tubular section;b. an internally, continuously threaded box connector on one end of saidtubular section, said threads being straight; c. an externally,continuously threaded pin connector on the other end of said tubularsection, said threads being straight; d. a first guide section on saidpin connector at one end of said threads thereon; e. a second guidesection on said pin connector at the other end of said threads thereon;f. a first receptacle in said box connector at one end of said threadstherein, said first receptacle adapted to receive such first guidesection of a like pipe joint; g. a second receptacle in said boxconnector at the other end of said threads therein, said secondreceptacle being adapted to receive such second guide section of a likepipe joint; and h. first and second abutment means carried by said pinconnector and said box connector, respectively; i. wherein such firstreceptacle may receive such first guide section, and such secondreceptacle may receive such second guide section, of a like pipe jointprior to threaded engagement of such threads on such pin connector andin such box connector and wherein such pin and box connectors of likepipe joints may be completely connected with said first and secondabutment means in mutual abutting engagement and with said threads onsaid pin connector and in said box connector loaded.
 55. A pipe joint asdefined in claim 54 wherein said first guide section and said firstreceptacle generally are larger in lateral dimension than said secondguide section and said second receptacle.
 56. A pipe joint as defined inclaim 54 wherein said threads of said pin connector and said threads ofsaid box connector are each back slanted to provide a wedge effecturging a tighter threaded engagement between such complementaryconnectors of like pipe joints in response to forces tending to expandsaid box connector.
 57. A pipe joint as defined in claim 54 furthercomprising seal means carried by said box connector and seat means aspart of said pin connector wherein such seal means may sealingly engagesuch seat means of a like pipe joint when such pin and box connectorsare engaged to connect said pipe joints.
 58. A pipe joint as defined inclaim 54 wherein the crests of said threads of said pin connector andthe crests of said threads of said box connector are parallel to thelongitudinal axis of said pipe joint.
 59. A method of making a threadedconnection between first and second longitudinal members, said membersincluding generally complementary continuous, straight threads and firstand second abutment means, respectively, comprising the steps of:a.inserting an end of said first longitudinal member into an end of saidsecond longitudinal member; b. inserting a first guide section of saidfirst longitudinal member in a first receptacle in said secondlongitudinal member and inserting a second guide section on said firstlongitudinal member in a second receptacle in said second longitudinalmember to align said first and second members; c. thereafter meshingsaid threads of said first and second longitudinal members; and d.rotating one said longitudinal member relative to the other saidlongitudinal member to fully engage said threads to completely connectsaid longitudinal members, placing said first and second abutment meansin mutual abutting engagement with said threads loaded.
 60. A connectorassembly comprising:a. a first connector member including a first guidesection and a second guide section axially displaced from, and ofgenerally lesser external lateral dimension than, said first guidesection; b. a second connector member for receiving said first connectormember, including a first receptacle, for receiving said first guidesection, and a second receptacle, for receiving said second guidesection, axially displaced from and of generally lesser internal lateraldimension than said first receptacle; c. tapered, essentially wedgeshaped external threads, as part of said first member, positionedgenerally axially between said first and second guide sections andcomprising back slanted landing surfaces; and d. tapered, essentiallywedge shaped internal threads, as part of said second member, positionedgenerally axially between said first and second receptacles, comprisingback slanted landing surfaces, and generally complementary to saidexternal threads for threaded engagement therewith, wherein the anglesof orientation of said internal and external thread landing surfaces aremutually supplementary; e. wherein said first and second guide sectionsmay be partially received by said first and second receptacles,respectively, to align said first and second members without threadedengagement between said external and internal threads, and wherein themeshing of said external and internal threads, with said respectivelanding surfaces positioned mutually flat against each other, provides awedging effect between said respective back slanted landing surfacesurging said external and internal threads into tighter engagement inresponse to forces tending to expand said second member.
 61. An assemblyas defined in claim 60 further comprising seal means carried by one ofsaid members for sealingly engaging the other of said members when saidfirst and second members are connected together in threaded engagementbetween said external and internal threads.
 62. As assembly as definedin claim 60 further comprising first and second abutment means carriedby said first and second members, respectively, whereby said first andsecond members may be completely connected with said first and secondabutment means in mutual abutting engagement and said back slantedlanding surfaces mutually wedged, but without said external and internalthreads completely meshed.
 63. As assembly as defined in claim 60wherein one of said guide sections comprises a frustoconical surface andthe corresponding receptacle comprises a frustoconical surface. 64.Connecting apparatus comprising:a. an externally threaded member, thethreads thereon being essentially wedge shaped and substantially tapereddownwardly toward an end of said externally threaded member andcomprising back slanted landing surfaces; b. said externally threadedmember further having a first guide section on one axial side of saidthreads and a second guide section on the other axial side of saidthreads; c. an internally threaded tubular member, the threads thereinbeing essentially wedge shaped and substantially tapered tocomplementarily receive said threads on said externally threaded memberand comprising back slanted landing surfaces, wherein the angles oforientation of said internal and external thread landing surfaces aremutually supplementary; d. said internally threaded member furtherhaving a first receptacle on one axial side of said internal threads anda second receptacle on the other axial side of said threads, whichreceptacles are sized to complementarily receive said first and secondguide sections of said externally threaded member, respectively; and e.said taper of said threads of both said externally threaded member andsaid internally threaded member permitting engagement of said first andsecond guide sections with said first and second receptacles,respectively, prior to mutual threaded engagement of said threads ofsaid externally and internally threaded members, and wherein the meshingof said external and internal threads, with said respective landingsurfaces positioned mutually flat against each other, provides a wedgingeffect between said respective back slanted landing surfaces urging saidexternal and internal threads into tighter engagement in response toforces tending to expand said internally threaded member.
 65. Apparatusas defined in claim 64 further comprising first and second abutmentmeans carried by said externally and internally threaded members,respectively, whereby said members may be completely connected with saidfirst and second abutment means in mutual abutting engagement and saidback slanted landing surfaces mutually wedged, but without said externaland internal threads completely meshed.
 66. Apparatus as defined inclaim 64 wherein one of said guide sections comprises a frustoconicalsurface and the corresponding receptacle comprises a frustoconicalsurface.
 67. Apparatus as defined in claim 64 further comprising sealmeans for sealingly connecting said externally and internally threadedmembers when said threads of said two members are in threadedengagement.
 68. A pipe joint comprising:a. a tubular section; b. aninternally threaded box connector on one end of said tubular section; c.an externally threaded pin connector on the other end of said tubularsection; d. a first guide section on said pin connector at one end ofsaid threads thereon; e. a second guide section on said pin connector atthe other end of said threads thereon; f. a first receptacle in said boxconnector at one end of said threads therein, said first receptacleadapted to receive such first guide section of a like pipe joint; and g.a second receptacle in said box connector at the other end of saidthreads therein, said second receptacle adapted to receive such secondguide section of a like pipe joint; h. wherein said threads on said pinconnector and in said box connector are essentially wedge shaped andgenerally tapered from the lateral dimensions of said first guidesection and said first receptacle, respectively, to the lateraldimensions of said second guide section and said second receptacle,respectively; i. wherein such first receptacle may receive such firstguide section, and such second receptacle may receive such second guidesection, of a like pipe joint prior to threaded engagement of suchthreads on such pin connector and in such box connector; and j. whereinsaid threads on said pin connector and said threads in said boxconnector have landing surfaces which are back slanted at mutuallysupplementary angles to provide a wedge effect, with said respectivelanding surfaces positioned mutually flat against each other, urging atighter threaded engagement between such complementary connectors oflike pipe joints in response to forces tending to expand said boxconnector.
 69. A pipe joint as defined in claim 68 further comprisingseal means carried by said box connector and seat means as part of saidpin connector wherein such seal means may sealingly engage such seatmeans of a like pipe joint when such pin and box connectors are engagedto connect said pipe joints.
 70. A pipe joint as defined in claim 68wherein at least one of said guide sections comprises a frustoconicalsurface, and the corresponding receptacle comprises a frustoconicalsurface.
 71. A pipe joint as defined in claim 68 further comprisingfirst and second abutment means carried by said pin connector and saidbox connector, respectively, whereby such pin and box connectors may becompletely connected with said first and second abutment means in mutualabutting engagement and said back slanted landing surfaces mutuallywedged, but without said external and internal threads completelymeshed.
 72. A method of making a threaded connection between first andsecond longitudinal members, said members including generallycomplementary, tapered, and essentially wedge shaped, threads with eachset of threads comprising back slanted landing surfaces at mutuallysupplementary angles, comprising the steps of:a. inserting an end ofsaid first longitudinal member into an end of said second longitudinalmember; b. inserting a first guide section on said first longitudinalmember in a first receptacle in said second longitudinal member andinserting a second guide section on said first longitudinal member in asecond receptacle in said second longitudinal member to align said firstand second members; c. thereafter meshing threads of said first andsecond longitudinal members; and d. rotating one said longitudinalmember relative to the other said longitudinal member to fully engagesaid threads, providing a wedging effect between said respective backslanted landing surfaces, with said respective landing surfacespositioned mutually flat against each other, urging the threads of saidfirst and second longitudinal members into tighter engagement inresponse to forces tending to expand the second member.
 73. A method asdefined in claim 72 further comprising placing first and second abutmentmeans, carried by said first and second members, respectively, in mutualabutting engagement with said first and second members completelyconnected and said back slanted landing surfaces mutually wedged, butwithout said threads completely meshed.